Andy McCarthy and others have strongly suggested that we must suspend the practice of allowing Muslims from Muslim-majority nations around the world to immigrate to the United States. I agree with them.

The reason is very simple: it's necessary for our national security and indeed may be necessary for our very survival.

A case in point, as Robert Spencer points out in FrontPage magazine: Quazi Mohammad Rexwanul Ahsan Nafis, arrested this week for trying to blow up the Federal Reserve Bank in New York. He was here on a student visa from Bangladesh, which is about 90% Muslim.

This Muslim came to the United States not to study but to kill. His stated purpose: "I don't want something that's like, small. I just want something big. Something very big ... that will shake the whole country, that will make America, not one step ahead, change of policy, and make one step ahead, for the Muslims ... that will make us one step closer to run the whole world." In his own words, he wanted to "destroy America." And we invited him in!

Here's the problem. Nobody who knew him could see this coming. In fact, they were all shocked, shocked I tell you, to learn that he was capable of such evil. Said his father: "He is very gentle and devoted to his studies."

He's far from the only one. Kifah Jayyousi was charged with "conspiring to kidnap, maim and murder" on behalf of Islam in Bosnia, Kosovo and Chechnya. But the superintendent of Detroit Public Schools said he was "a great guy, one of the nicest people I've ever met."

Even Americans who convert to Islam can fool you, which means we have enough problems with jihadism internally that it is foolish in the extreme to import more.

Muslim convert Christopher Paul was charged with "providing material support to terrorists, conspiracy to provide support to terrorists and conspiracy to use a weapon of mass destruction." Here's what one of his Muslim friends from CAIR said: "From the things I know, he is a loving husband and he has a wife and parents in town. They are a good family together."

Muslim convert John Walker Lindh was captured in Afghanistan fighting against American troops. Not to worry, said his father. "In simple terms, this is the story of a decent and honorable young man embarked on a spiritual quest."

All of Maj. Nidal Malik Hasan's neighbors thought he was a terrific guy, right up until the day he started shooting up Ft. Hood in the name of Allah. The supervisor of clinical services at Ft. Hood said Hasan provided excellent care to his patients. "You wouldn't think that someone who works in your facility and provided excellent care for his patients, which he did, could do something like this."

Praising his work ethic, she added, "In my personal interactions, there was never any indication he would do something like this." According to the NBC affiliate in Dallas-Ft. Worth, "To neighbors, Hasan was described as a generous man and a good neighbor."

Spencer quotes the Nazi genocidal maniac Heinrich Himmler, speaking to his fellow SS leaders: "Most of you know what it means to see a hundred corpses lying together, five hundred, or a thousand. To have gone through this and yet — apart from a few exceptions, examples of human weakness — to have remained decent fellows, this is what has made us hard..."

The fact that someone may be a "decent fellow" from all appearances should not make us blind to the dark, dangerous and violent spirit of Islam that may be lurking in the heart of people who appear harmless to a naive and unsuspecting people.

Spencer says this in his closing paragraph: "Today's jihad terrorists are likewise the adherents of a totalitarian, genocidal ideology that teaches them that murders committed under certain circumstances are a good thing. And those murders, here again, are not committed for their own sake, but for the sake of a societal vision hardly less draconian and evil than that of Adolf Hitler."

While it is true that there are moderate Muslims, there is no such thing as moderate Islam. And while there are moderate Muslims, no one has yet developed a error-free way to tell the difference between the Muslims we have to worry about and the ones we don't.

Until that day comes, we must be cautious about them all.

(Unless otherwise noted, the opinions expressed are the author's and do not necessarily reflect the views of the American Family Association or American Family Radio.)

Bryan Fischer

Bryan Fischer is the host of the daily 'Focal Point' radio talk program on AFR Talk, a division of the American Family Association. 'Focal Point' airs live from 1-3 pm Central Time, and is also simulcast on the AFA Channel, which can be seen on the Sky Angel network.